It is known that pyrazolotriazole compounds are useful photographic dye forming couplers. Particularly, it is known in the art that 1H-Pyrazolo[1,5-b][1,2,4]triazole compounds are magenta dye forming couplers. Examples are EP 119,860; U.S. Pat. No. 4,621,046; JP 62-172363; DE 19921733, and U.S. Pat. No. 5,998,122.
They are most commonly prepared through a multi-step procedure, as shown in Scheme 1. Examples are shown in JP 07-082252, U.S. Pat. No. 6,020,498, and U.S. Pat. No. 5,262,542.

These syntheses are long, comprising at least 4 steps. They require the use of nitrites or activated forms of amides as starting materials, some of which are toxic and/or not readily available.
There have been efforts to shorten the number of synthesis steps and increase yield and purity of these important intermediates for color photography. Recent examples are U.S. Pat. No. 6,555,711 and U.S. Pat. No. 6,657,066.
Prior art relating to diaminopyrazole compounds can be found in U.S. Pat. No. 5,723,623 and JP 08-069096 and [Sliskovic, D. R.; Siegel, M.; Lin, Y. I. Synthesis, 1986, 1, 71], and more recently in [Blake, A. J.; Clarke, D.; Mares, R. W.; McNab, H. Org. Biomol. Chem. 2003, 1, 4268]. The prior art reaction is pictured below, wherein E is a heteroatom (O, N or S) or heterogroup (a group connected by a O, N or S atom) and the reaction employed to close the ring requires the use of external heat and a base.

The 1,5-diaminopyrazole compound and its synthesis are known in the art (see prior art described above, and a review of the use of the reagent hydroxylamine-O-sulfonic acid can be found at Wallace, R. G. Organic Preparations and Procedures Int. 14(4), 265–307, 1982).
It remains a problem to be solved to provide a synthesis for 1H-Pyrazolo[1,5-b][1,2,4]triazole compounds that can be carried out in fewer steps.